1. Field of the Invention
The present invention pertains to a porous media barrier or impingement type air filter unit including an improved filter element construction and a multiple jet reverse air flow backflushing type filter cleaning system particularly adapted for a power sweeper and other low profile, compact installation.
2. Background
In the art of power sweepers and similar types of equipment various attempts have been made to develop air filters for removing the particulate matter entrained in the sweeper vacuum air flow system. Conventional power sweepers are typically provided with a hopper which may include a vacuum or suction air flow system including a filter which is periodically cleaned by vibrating the filter element or simply by requiring that the filter element be removed and replaced. There are several disadvantages associated with prior art type power sweeper filters and an important aspect of the filter system requires that the filter be very compact, be capable of sustaining high loadings of particulate material entrained in the sweeper suction air stream and be capable of automatic or selective cleaning operations without removing the filter from the hopper.
My above referenced U.S. patent applications pertain to an improvement in porous media barrier type air filters wherein a substantial amount of reverse direction flow of cleaning air is provided using a multple jet nozzle arrangement for thoroughly cleaning filters which are subject to particularly high air flow rates. The present invention pertains to further improvements in air filter units and filter elements including a multiple jet reverse air flow filter cleaning or backflushing system and which is particularly attractive for applications such as industrial power floor or street sweepers and the like.